AGE AT ONSET AND LANGUAGE DISTURBANCES IN ALZHEIMERS-DISEASE

This study examined the effect of age at symptom onset of Alzheimer's disease (AD) on the pattern of language disturbance. We assessed 150 c onsecutive patients with a clinical diagnosis of mild-to-moderate AD u sing the Western Aphasia Battery and a 100-item picture-naming test. A multivariate linear regression analysis examined the effect of age at onset after controlling for gender, education, severity of dementia a nd duration of the disease. Patients with early onset performed signif icantly worse than did patients with late onset on the word comprehens ion and sequential commands subtests. On the other hand, late-onset pa tients performed more poorly than early-onset patients on the picture- naming test in a subgroup with mild language deficits. However, the tr end disappeared in other subgroups with more degraded language functio n. We consider that the concomitant effects of normal aging worsened t he picture-naming deficits in the late-onset patients, and the rapid d ecline of naming ability in the early-onset patients masked the aging effect with the progression of language deficits. The deterioration of word comprehension and the rapid decline of naming ability are the ch aracteristics of early-onset patients. The different patterns of langu age deficits between early- and late-onset patients may correspond to the genetic heterogeneity of AD. (C) 1998 Elsevier Science Ltd. All ri ghts reserved.